Application of Ribotyping and rDNA Internal Space Analysis (RISA) for Assessment of Microflora in Brewery Environments

Abstract

The applications of ribotyping and rDNA internal space analysis (RISA) were evaluated for assessment of microflora in brewery environments. For this purpose, approximately 2,000 strains isolated in our breweries were analyzed by ribotyping, and the database was constructed using all the data acquired. The strains that displayed unidentifiable ribopatterns were presumptively identified by 16S rDNA analysis, and novel ribopatterns were registered in our database as Custom ID patterns. As a result, it was demonstrated that ribotyping is capable of discriminating the brewery isolates on the strain level and well suited to the detailed analysis of microflora in brewery environments. We have also successfully accumulated an enormous database of the strains isolated from the brewery environments. We further evaluated RISA as an inexpensive and rapid alternative to ribotyping. As a consequence, RISA was shown to distinguish strains broadly on the species level, which is sufficient for the practical assessment of brewery isolates. Because this technique has an advantage in terms of cost and time required for analysis, RISA was also considered to complement ribotyping as a prescreening method. On the basis of these results, we have developed a reliable system for assessing the microflora in brewery environments by combining ribotyping and RISA.